When operating a radio base station, it is necessary for an operation side to continuously invest in the radio base station in order to meet a traffic demand which is caused by increase of user traffic in a mobile network. Therefore, a vast amount of OPEX (operating expenditure) and CAPEX (capital expenditure) is necessary.
As a method to solve the above-mentioned problem, a method of introducing a C-RAN (Centralized Radio Access Network) technology and a virtualization technology is exemplified. According to the method, a radio base station function is separated into a control part (DU: Digital Unit) and an antenna part (RU: Radio Unit), and DU is realized by the virtualization technology using VM (Virtual Machine). Thereby, it is possible to carry out centralized management and control of DU with MANO (Management and Orchestration), and consequently it is possible to reduce OPEX, CAPEX, and electric power consumption.
However, according to the above-mentioned method, since it is necessary to carry out manual adjustment of a computation resource (number of CPUs (Central Processing Unit), a memory size, and the like) which is assigned to a virtual node of DU, it cannot be expected to realize reduction of OPEX which is caused by adjusting the computation resource. Moreover, since distribution of the user traffic is largely changed dependently on a time zone or a location, it is difficult to optimize the computation resource of each virtual node on manual.
Meanwhile, according to the method described by a patent literature (PTL) 1, a SON (Self Organizing Network) server collects information from a radio base station, and determines whether to reconstruct a group cell or not based on a totalized result on a relation between a source base station and a destination base station of a moving station to which hand-over is carried out. According to the method, it is possible to carry out reconstruction of the group cell with ease.
[Patent literature 1] Japanese Patent Application Laid-Open Publication No. 2012-004837
However, according to the method described by PTL 1, it is difficult to realize reduction of OPEX which is caused by adjusting the computation resource of the virtual node realizing DU.